The 41-year-old singer was approached by 'X Factor' boss and former 'American Idol' judge Simon Cowell about joining the show's much-speculated judging panel but decided to take part in Simon Fuller's rival talent search instead because it has been around for longer and "seemed a better fit".
She said: "We did talk about 'The X Factor' for a little bit. But at the end of the day, thinking about my career and everything that was going on, when the opportunity to do 'Idol' came along it seemed a better fit.
"'Idol' has been a show for so many years. It's an institution. To be involved in something like that felt really great."
The mother-of-two – who reportedly signed a $12m deal to join the panel of 'American Idol', alongside Aerosmith's Steven Tyler and Randy Jackson – says although she is enjoying mentoring young hopefuls she is unsure whether she will return to the show next year.
She told the Daily Star newspaper: "I don't know if I will do another season. I'm taking it day by day at the moment and we'll see what happens.
"I've been having a great time, I can't lie. I'm really enjoying it and having fun and enjoying working with the contestants."
Jennifer particularly likes being on the show because while she shares her experience and knowledge with contestants she gains inspiration from them.
She said: "You can't help but learn from them. You're talking about performing and singing and when you're watching them you see them and think: 'I do that.' It's been a great exchange back and forth."